Category: Public Works
Client: Municipal Authority in California
Condition assessment and repair recommendation for a sewage treatment plant.
Coating Failure
The visual inspection showed that the exterior of the structure was generally in good condition, but the roof dome had some minor cracking. The interior coating had several cracks, delamination, and minor spalls
Testing for Metal Thickness
The upper skimmer arms had broken ties and exhibited heavy corrosion, especially on metal angles. The intermediate shaft also showed substantial corrosion at some locations.The sewage generates hydrogen sulfide. Hydrogen sulfide caused deterioration in concrete and corrosion of exposed metal parts such as skimmer.
Condition of Reinforcement
The testing consisted of coring, inspection of reinforcing steel nondestructive impact echo tests, Rebound hammer tests, coring, strength tests, chloride tests,& concrete petrography.
Repairs were designed to extend the service life structure by 25 years. The repairs consisted of epoxy injection, spall repair, applying allow permeability overlay, and a 100% solid coating to resist hydrogen sulfide related deterioration.